1. Field of the Invention.
The present invention relates generally to improvements in devices for fixing skeletal fractures and, more particularly, but not by way of limitation, for fixing fractures of the femur.
2. Brief Description of the Prior Art.
In the treatment of fractures of the femur, it has become standard practice to utilize an appliance to fix separated portions of the femur while knitting of such portions occurs. A variety of such appliances are known. For example, U.S. Pat. No. 3,561,437, issued to Orlich, discloses an apparatus which, in one embodiment, is comprised of a plate that can be attached to the lateral side of the femur via screws and a nail that slides in a channel member at the top of the plate for implantation in the head and neck of the femur. In a second embodiment disclosed in the Orlich patent, a nail implanted in the intramedullary canal is used in place of the plate. Another such appliance, disclosed in U.S. Pat. No. 3,439,671, issued to Kuntscher, is comprised of an intramedullary nail that is extended into the intramedullary canal and passes through a hole formed through a femoral spike, or cross nail, that is extended into the head and neck of the femur. Yet another such appliance is that disclosed in U.S. Pat. No. 3,433,220, issued to Zickel, such appliance being comprised of an intramedullary rod that is implanted in the intramedullary canal and has a hole formed through portions thereof near the upper end of the rod to receive a cross nail that is extended into the head and neck of the femur. A locking screw is introduced through the upper end of the intramedullary rod to engage the cross nail and fix the cross nail in position within the hole through the intramedullary rod.
While these prior art appliances have brought about important advances in the treatment of femoral fractures, problems have remained with their use. In general, a particular appliance is limited in the types of fractures for which the appliance is suited. Thus, for example, the Kuntscher appliance is well adapted for the treatment of intertrochanteric fractures but is not well suited for the treatment of comminuted subtrochanteric fractures. In particular, the cross nail of the Kuntscher appliance can shift along the intramedullary nail thereof in response to repeated, small forces that are applied to the cross nail during normal activities of the patient causing shortening of comminuted subtrochanteric fractures of the femur. Similarly, the Zickel appliance is well suited for transverse subtrochanteric fractures of the femur but is not well adapted to fractures that occur in the intertrochanteric, neck and head portions of the femur or comminuted subtrochanteric fractures of the femur. Neither of these two appliances are particularly well adapted to the treatment of fractures of the femoral neck, intertrochanteric region or subtrochanteric region of the femur that occur in association with ipsilateral femoral shaft fractures.
While the problems encountered with the Kuntscher and Zickel appliances can, to some extent, be overcome by using an appliance such as that disclosed by Orlich to include a plate screwed to the lateral surface of the femur, the use of such a plate introduces other problems. In particular, the positioning of the plate on the lateral cortex results in the weight of the body being transmitted to the plate via a lengthy lever arm so that breakage can occur at the upper end of the plate unless upper portions of the plate and connecting portions of the nail are provided with an undesirable bulk. Moreover, the affixation of a plate to the lateral cortex of the femur requires that an incision be made along a considerable extent of the femoral shaft and, in particular, along portions of the femur in which the fracture has occurred. A lengthy incision enhances the likelihood of infection, a problem that can be especially severe when the infection occurs to portions of the bone that have been fractured and whose knitting is the purpose of the use of the appliance.